If successful, remove the contact in your handset and re-add it using the dialing pattern that was successful.

Dial *31# and then the 10 or 11 digit number. (*31# changes the caller ID settings for just one call).

If successful, your T-Mobile service is working properly. The other party has a service or application preventing the call from completing.

Turn off your handset.

Wait 5 seconds and turn on your handset.

Dial *31# and then the 10 or 11 digit number. (*31# changes the caller ID settings for just one call).

If the call fails, and you saw a "Call Failed," "Call Ended," disconnected, or heard 1 or 2 rings and then the call dropped, the other party has a service or application preventing the call from completing.